ABSTRACT
The response of systolic blood pressure (SBP) to pedalling exercise was studied in 32 healthy young men. The subjects performed the exercise at different intensities for 3 min using an incremental loading method. The first work load was 30W and increased by 30W until the heart rate (HR) reached about 170 bpm. SBP at HR 100. 160 bpm (SBP@HR 100-160) was calculated from the cubic regression equation in each subject. Mean SBP and SEM at HR 100, 110, 120, 130, 140, 150, 160 were 143.9 (2.49), 152.9 (2.79), 161.6 (3.02), 170.0 (3.16), 177.8 (3.25), 184.5 (3.34), and 189.7 (3.45) mmHg, respectively. However, the rate of elevation of SBP was zero at HR 175 bpm, which was calculated from the cubic regression equation. This may indicate that SBP is inhibited by baroreceptors and other factors at HR above 170 bpm. There were no significant relationships between SBPs@HR 100-160 and indices of aerobic capacity such as maximal oxygen consumption or PWC 170. Double product (DP) as an index of oxygen consumption by cardiac muscle increased with HR without any reduction in its rate of elevation during exercise.